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Myo-inositol uptake by cultured calf retinal pigment epithelial cells: regulation by glucose

Conference · · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)
OSTI ID:6802453
Confluent primary (P-1) or subcultured passage 2 or 3 (P-2, P-3) calf retinal pigment epithelial cells (RPE) were incubated with (/sup 3/H)-myo-inositol (MI, 100-200 ..mu..M) in balanced salt solution (BSS), for 5 to 60 min at 37/sup 0/C. MI uptake into RPE (P-2, 5 days old) was saturable with K/sub m/ of 147 ..mu..M and V/sub max/ of 5.5 pmole/min/..mu..g DNA. P-1 or P-2 incubated with 10 ..mu..M MI for 40 min accumulated MI against a concentration gradient ((MI)in/(MI)out > 20). Replacement of 150 mM NaCl in BSS by 150 mM choline-Cl reduced the uptake of MI by 87%. MI uptake was inhibited (39%) when cells were incubated in BSS in the absence of Ca Cl/sub 2/. Transport of MI into RPE incubated in the presence of phloridzin, ouabain or 2,4-dinitrophenol (1 mM each) for 10 min was inhibited by 65, 37 and 21%, respectively. ..cap alpha..-D-Glucose (20 mM) in the incubation media inhibited MI uptake into primary (or P-2) cultured RPE by 30 or 43% when cells were incubated for 10 or 60 min, respectively. The ability of RPE cells, grown in the presence of 50 mM glucose for 15-25 days, to concentrate MI (40 ..mu..M) was reduced up to 41%. Cultured RPE cells accumulated myo-inositol by an active transport system, sensitive to ouabain, DNP and phloridzin. High glucose in the incubation media or in the growth media inhibited the uptake of MI into calf RPE cells.
Research Organization:
Univ. of Pennsylvania, Philadelphia
OSTI ID:
6802453
Report Number(s):
CONF-8604222-
Conference Information:
Journal Name: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) Journal Volume: 45:4
Country of Publication:
United States
Language:
English